A retractor is a surgical instrument by which a surgeon can either actively separate the edges of a surgical incision or wound, or can hold back underlying organs and tissues, so that body parts under the incision are accessed.
The term retractor is also used to describe the distinct, hand-cranked devices such as rib spreaders (also known as thoracic retractors, or distractors) with which surgeons may forcefully drive tissues apart to obtain the exposure. For specialized situations such as spinal surgery retractors have been fitted both with suction and with fiberoptic lights to keep a surgical wound dry and illuminated.
Retractors are available in many shapes, sizes, and styles. The general term retractor usually describes a simple handheld steel tool possessing a curved, hooked, or angled blade fitted with a comfortable handle, that when in place maintains the desired position of a given region of tissue.
There are various ophthalmic procedures that require the dilation of the pupil. For example, a lens with a cataract is typically removed from the eye by phacoemulsification. This procedure breaks up the lens typically with an ultrasonically driven tool. The tool has an aspiration port that aspirates the broken lens material from the patient's ocular-chamber. It is desirable to expand the pupil during phacoemulsification to provide the surgeon with a wide view of the lens. One technique for expanding the pupil includes pulling back or retracting the iris with what is referred to as an iris retractor, and holding the iris at its outer edges.